1. Field of the Invention
The present invention relates generally to chip antennas and, more particularly, to chip antennas used in mobile communications and local area networks (LAN).
2. Description of the Related Art
Referring to a side view of a conventional type of chip antenna shown in FIG. 3, a chip antenna generally indicated by 50 is comprised of: a rectangular-prism-shaped insulator 51 formed by laminating insulating layers (not shown) made from insulating powder, such as alumina or steatite; a conductor 52 made from silver or silver-palladium and formed in a coil-like shape inside the insulator 51; a magnetic member 53 made from magnetic powder, such as ferrite powder, and formed inside the insulator 51 and the coil-shaped conductor 52; and external connecting terminals 54a and 54b. The connecting terminals 54a and 54b are attached to the ends of a lead (not shown) of the conductor 52 and baked after the insulator 51, the conductor 52, and the magnetic member 53 are integrally sintered. Namely, the chip antenna 50 is constructed in such a manner that the coil-shaped conductor 52 is wound around the magnetic member 53, and both the elements are encapsulated by the insulator 51.
In the above conventional type of chip antenna, the resonant frequency of the antenna is controlled by the relative magnetic permeability of the magnetic member formed within the coil-shaped conductor. It is necessary that the sintering conditions for the insulating layers, the magnetic layer and the conductor be consistent because the individual elements are integrally sintered after they have been laminated by printing. If, however, a low-melting-point metal, such as gold, silver or copper, is used as a metal for the conductor, the selection for the materials used for the magnetic member should be restricted due to the use of low-melting-point metal. This makes it impossible to obtain desired antenna characteristics, such as the resonant frequency and bandwidth.